The paint system of commercial vehicles is subject to exacting requirements. In a typical system, atop a metal substrate optionally coated with an electrocoat, a filler coat and a topcoat are applied. The topcoat typically unites the functions of a basecoat and a clearcoat with one another. Accordingly, a topcoat comprises pigments, for example, and therefore substantially governs the overall color impression given by the finish. Moreover, it also possesses typical properties characteristic of a clearcoat, such as a corresponding scratch resistance, for example.
Both the filler and the topcoat are typically solvent-based systems. In many cases, the finishing of commercial vehicles is not automated. This means that the coating materials in question are applied by hand—that is, for example, by means of spray application. In such cases, two-component paint systems are principally used that permit curing at moderate temperatures. In a resultant finish, the adhesion between filler coat and topcoat continues to be a major problem.